1-Thiadiazolyl-5-morpholinoimidazolidinones

ABSTRACT

This invention discloses new compounds of the formula ##STR1## WHEREIN R 1  is selected from the group consisting of alkyl, cycloalkyl, alkenyl, haloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl; R 2  is selected from the group consisting of alkyl, alkenyl, haloalkyl and ##STR2## wherein R 3  and R 4  are each selected from the group consisting of hydrogen and alkyl; X is selected from the group consisting of alkyl and halogen; and n is an integer from 0 to 3. Further disclosed is the herbicidal utility of the foregoing compounds.

This invention relates to new compositions of matter and morespecifically relates to new chemical compounds of the formula ##STR3##wherein R¹ is selected from the group consisting of alkyl, cycloalkyl,alkenyl, haloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl;R² is selected from the group consisting of alkyl, alkenyl, haloalkyland ##STR4## wherein R³ and R⁴ are each selected from the groupconsisting of hydrogen and alkyl; X is selected from the groupconsisting of alkyl and halogen; and n is an integer from 0 to 3.

The compounds of the present invention are unexpectedly useful asherbicides.

In a preferred embodiment of this invention R¹ is selected from thegroup consisting of lower alkyl, cycloalkyl of from 3 to 7 carbon atoms,lower alkenyl, lower chloroalkyl, lower bromoalkyl, trifluoromethyl,lower alkoxy, lower alkylthio, lower alkylsulfonyl and loweralkylsulfinyl; R² is selected from the group consisting of lower alkyl,lower alkenyl, lower haloalkyl and propargyl; X is selected from thegroup consisting of lower alkyl, chlorine and bromine; and n is aninteger from 0 to 2.

The term "lower" as used herein designates a straight or branched carbonchain of up to six carbon atoms.

The compounds of the present invention can be prepared by reacting acompound of the formula ##STR5## wherein R¹ and R² are as heretoforedescribed, with morpholine or a substituted morpholine of the formula##STR6## wherein X and n are as heretofore described. This reaction canbe effected by combining the compound of formula II with an aboutequimolar amount or excess molar amount of the morpholine of formula IIIin an inert organic reaction medium, such as heptane or toluene, andthen heating the reaction mixture, with stirring, at its refluxtemperature and azeotropically removing the water of reaction. Afterthis time the reaction mixture can be cooled, and the desired productcan be recovered by filtration if formed as a precipitate or uponevaporation of the organic reaction medium if soluble therein. Theproduct can then be purified by conventional means such asrecrystallization and the like.

The compounds of formula II can be readily prepared by heating acompound of the formula ##STR7## wherein R¹ and R² are as heretoforedescribed and R⁵ and R⁶ are methyl or ethyl, in a dilute, aqueous,acidic reaction medium for a period of about 10 to about 60 minutes.Temperatures of from about 70° C to the reflux temperature of thereaction mixture can be utilized. The reaction medium can comprise adilute, aqueous inorganic acid such as hydrochloric acid at aconcentration of from about 0.5 to about 5 percent. Upon completion ofthe reaction the desired product can be recovered as a precipitate bycooling the reaction mixture. This product can be used as such or can befurther purified by conventional means such as recrystallization and thelike.

The compounds of formula IV can be prepared by reacting a molar amountof an isocyanate dimer of the formula ##STR8## wherein R¹ is asheretofore described, with about two molar amounts of a dimethyl acetalof the formula ##STR9## wherein R² is as heretofore described. Thisreaction can be effected by heating a mixture of the isocyanate dimerand the acetal in an inert organic reaction medium such as benzene atthe reflux temperature of the reaction mixture. Heating at reflux can becontinued for a period of from about 2 to about 30 minutes to ensurecompletion of the reaction. After this time the desired product can berecovered upon evaporation of the reaction medium and can be used assuch or can be further purified by standard techniques in the art.

The isocyanate dimer of formula V can be prepared by reacting athiadiazole of the formula ##STR10## wherein R¹ is as heretoforedescribed, with phosgene. This reaction can be effected by adding aslurry or solution of the thiadiazole, in a suitable organic solventsuch as ethyl acetate, to a saturated solution of phosgene in an organicsolvent such as ethyl acetate. The resulting mixture can be stirred atambient temperatures for a period of from about 4 to about 24 hours. Thereaction mixture can then be purged with nitrogen gas to removeunreacted phosgene. The desired product can then be recovered byfiltration, if formed as a precipitate, or upon evaporation of theorganic solvent used if soluble therein. This product can be used assuch or can be further purified as desired.

Exemplary thiadiazoles of formula VII useful for preparing the compoundsof the present invention are 5-methyl-2-amino-1,3,4-thiadiazole,5-ethyl-2-amino-1,3,4-thiadiazole, 5-propyl-2-amino-1,3,4-thiadiazole,5-t-butyl-2-amino-1,3,4-thiadiazole, 5-allyl-2-amino-1,3,4-thiadiazole,5-pent-3-enyl-2-amino-1,3,4-thiadiazole,5-chloromethyl-2-amino-1,3,4-thiadiazle,5-β-chloroethyl-2-amino-1,3,4-thiadiazole, 5-γ-chloropropyl-2-amino-1,3,4-thiadiazole,5-trichloromethyl-2-amino-1,3,4-thiadiazole,5-trifluoromethyl-2-amino-1,3,4-thiadiazole,5-methoxy-2-amino-1,3,4-thiadiazole, 5-ethoxy-2-amino-1,3,4-thiadiazole,5-propoxy-2-amino-1,3,4-thiadiazole,5-butyloxy-2-amino-1,3,4-thiadiazole,5-hexyloxy-2-amino-1,3,4-thiadiazole,5-methylthio-2-amino-1,3,4-thiadiazole,5-ethylthio-2-amino-1,3,4-thiadiazole, 5-propylthio-2-amino-1,3,4-thiadiazole, 5-butylthio-2-amino-1,3,4-thiadiazole,5-methylsulfonyl-2-amino-1,3,4-thiadiazole,5-ethylsulfonyl-2-amino-1,3,4-thiadiazole,5-butylsulfonyl-2-amino-1,3,4-thiadiazole,5-methylsulfinyl-2-amino-1,3,4-thiadiazole,5-ethylsulfinyl-2-amino-1,3,4-thiadiazole,5-propylsulfinyl-2-amino-1,3,4-thiadiazole,5-butylsulfinyl-2-amino-1,3,4-thiadiazole and the like.

Exemplary suitable acetals of formula VI for preparing the compounds ofthis invention are the dimethyl acetal of 2-methylaminoacetaldehyde, thedimethyl acetal of 2-ethylaminoacetaldehyde, the dimethyl acetal of2-propylaminoacetaldehyde, the dimethyl acetal of2-butylaminoacetaldehyde, the dimethyl acetal of2-pentylaminoacetaldehyde and the dimethyl acetal of2-hexylaminoacetaldehyde.

Exemplary compounds of formula III are morpholine, 3-methylmorpholine,3,5-dimethylmorpholine, 3-chloromorpholine, 3-bromomorpholine,3,5-dichloromorpholine, 3,3,5,5-tetramethylmorpholine,2-ethylmorpholine, 3-propylmorpholine, 3-hexylmorpholine,2-methyl-5-chloromorpholine and the like.

The manner in which the compounds of the present invention can beprepared is more specifically illustrated in the following examples.

EXAMPLE 1 Preparation of 5-Trifluoromethyl-1,3,4-thiadiazol-2-ylIsocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) was chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-trifluoromethyl-2-amino-1,3,4-thiadiazole (45 grams) inethyl acetate (300 ml) was added to the reaction vessel, and theresulting mixture was stirred for a period of about 16 hours resultingin the formation of precipitate. The reaction mixture was then purgedwith nitrogen gas to remove unreacted phosgene. The purged mixture wasfiltered to recover 48 grams of a white solid. This solid wasrecrystallized from dimethyl formamide to yield the desired product5-trifluoromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 2 Preparation of the Dimethyl Acetal of2-[1-Methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureidoacetaldehyde

A mixture of 5-trifluoromethyl-1,3,4-thiadiazol- 2-yl isocyanate dimer(9.5 grams), the dimethyl acetal of 2-methylaminoacetaldehyde (5.8grams) and benzene (60 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer and reflux condenser. The reactionmixture is heated at reflux for a period of about 15 minutes. After thistime the mixture is stripped of benzene under reduced pressure to yielda solid product as the residue. This product is recrystallized fromheptane to yield the desired product the dimethyl acetal of2-[1-methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde having a melting point of 101° to 102° C.

EXAMPLE 3 Preparation of 1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml)were charged into a glass reaction vessel equipped with a mechanicalstirrer, thermometer and reflux condenser. The reaction mixture washeated at reflux for a period of about 15 minutes. The reaction mixturewas then filtered while hot and the filtrate was cooled, resulting inthe formation of a precipitate. The precipitate was recovered byfiltration, was dried and was recrystallized from an ethylacetate-hexane mixture to yield the desired product1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one having a melting point of 136°to 138° C.

EXAMPLE 4 Preparation of 1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one (13.1 grams) and heptane (100ml) were charged into a glass reaction vessel equipped with a mechanicalstirrer, thermometer, Dean-Stark trap and reflux condenser. Morpholine(5.0 grams) was added to the reaction vessel, and the mixture was heatedat reflux while removing the water as it was formed. After no more waterwas given off, the reaction mixture was cooled, resulting in theprecipitation of a crystalline solid. The solid was recovered byfiltration and was recrystallized from a water-methanol mixture to yieldthe desired product 1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one having a melting point of100° to 102° C.

EXAMPLE 5 Preparation of 5-t-Butyl-1,3,4-thiadiazol-2-yl IsocyanateDimer

A saturated solution of phosgene in ethyl acetate (100 ml) was chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-t-butyl-2-amino-1,3,4-thiadiazole (10 grams) in ethylacetate (300 ml) was added to the reaction vessel, and the resultingmixture was stirred for a period of about 16 hours resulting in theformation of a precipitate. The reaction mixture was then purged withnitrogen gas to remove unreacted phosgene. The purged mixture was thenfiltered to recover the desired product 5-t-butyl-1,3,4-thiadiazol-2-ylisocyanate dimer as a solid having a melting point of 261° to 263° C.

EXAMPLE 6 Preparation of the Dimethyl Acetal of2-[1-Methyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde

A mixture of 5-t-butyl-1,3,4-thiadiazol-2-yl isocyanate dimer (6 grams),the dimethyl acetal of 2-methylaminoacetaldehyde (3.9 grams) and benzene(50 ml) were charged into a glass reaction flask equipped with amechanical stirrer and reflux condenser. The reaction mixture was heatedat reflux, with stirring for a period of about 5 minutes. After thistime the reaction mixture was stripped of benzene to yield an oil whichsolidified upon standing. The resulting solid was then recrystallizedfrom pentane to yield the desired product the dimethyl acetal of2-[1-methyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehydehaving a melting point of 80° to 82° C.

EXAMPLE 7 Preparation of 1-(5-t-Butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde (16grams), concentrated hydrochloric acid (10 ml) and water (500 ml) werecharged into a glass reaction vessel equipped with a mechanical stirrer,thermometer and reflux condenser. The reaction mixture was heated atreflux for a period of about 15 minutes. The reaction mixture wasfiltered while hot, and the filtrate was then cooled, resulting in theformation of a precipitate. The precipitate was recovered by filtration,dried and was recrystallized from a benzene-hexane mixture to yield thedesired product 1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one having a melting point of 133°to 134° C.

Example 8 Preparation of 1-(5-t-Butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-t-Butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one (13.4 grams), morpholine (5.0)and heptane (100 ml) are charged into a glass reaction vessel equippedwith a mechanical stirrer, thermometer, reflux condenser and Dean-Starktrap. The reaction mixture is heated at reflux, and the water ofreaction is removed as it is formed by azeotroping. After no more wateris given off, the reaction mixture is stripped of solvent to yield thedesired product 1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one.

EXAMPLE 9 Preparation of 5-Hexyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-hexyl-2-amino-1,3,4-thiadiazole (40 grams) in ethyl acetate(300 ml) is added to the reaction vessel, and the resulting mixture isstirred for a period of about 16 hours, resulting in the formation of aprecipitate. The reaction mixture is then purged with nitrogen gas toremove unreacted phosgene. The purged mixture is then filtered torecover the precipitate. The precipitate is then recrystallized to yieldthe desired product 5-hexyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 10 Preparation of the Dimethyl Acetal of2-[1-Ethyl-3-(5-hexyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde

A mixture of 5-hexyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole),the dimethyl acetal of 2-ethylaminoacetaldehyde (0.1 mole) and benzene(60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. The residue is then recrystallized to yield the desiredproduct the dimethyl acetal of2-[1-ethyl-3-(5-hexyl-1,3,4-thiadiazol-2-yl)ureido] -acetaldehyde.

EXAMPLE 11 Preparation of 1-(5-Hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-ethyl-3-(5-hexyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde (15grams), water (400 ml) and hydrochloric acid (4 ml) are charged into aglass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized to yield thedesired product 1-(5-hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 12 Preparation of 1-(5-Hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one (0.1 mole), morpholine (0.11mole) and benzene (100 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer, thermometer, reflux condenser andDean-Stark trap. The reaction mixture is heated at reflux, and the waterof reaction is removed as it is formed. After no more water is formed,the reaction mixture is stripped of solvent under reduced pressure toyield the desired product 1-(5-hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one as the residue.

EXAMPLE 13 Preparation of 5-Methoxy-1,3,4-thiadiazol-2-yl IsocyanateDimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-methoxy-2-amino-1,3,4-thiadiazole (40 grams) in ethylacetate (300 ml) is added to the reaction vessel, and the resultingmixture is stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture is then purged withnitrogen gas to remove unreacted phosgene. The purged mixture is thenfiltered to recover the precipitate. The precipitate is thenrecrystallized to yield the desired product5-methoxy-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 14 Preparation of the Dimethyl Acetal of2-[1-Ethyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde

A mixture of 5-methoxy-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05mole), the dimethyl acetal of 2-ethylaminoacetaldehyde (0.1 mole) andbenzene (60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. The residue is then recrystallized to yield the desiredproduct the dimethyl acetal of2-[1-ethyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde.

EXAMPLE 15 Preparation of 1-(5-Methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-ethyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde (15grams), water (400 ml) and hydrochloric acid (4 ml) are charged into aglass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized to yield thedesired product 1-(5-methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 16 Preparation of 1-(5-Methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-hydroxy-1,3-imidazolidin-2-one (0.1 mole), morpholine (0.11mole) and benzene (100 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer, thermometer, reflux condenser andDean-Stark trap. The reaction mixture is heated at reflux, and the waterof reaction is removed as it is formed. After no more water is formed,the reaction mixture is stripped of solvent under reduced pressure toyield the desired product 1-(5-methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one as the residue.

EXAMPLE 17 Preparation of 5-Methylthio-1,3,4-thiadiazol-2-yl IsocyanateDimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-methylthio-2-amino-1,3,4-thiadiazole (45 grams) in ethylacetate (300 ml) is added to the reaction vessel, and the resultingmixture is stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture is then purged withnitrogen gas to remove unreacted phosgene. The purged mixture isfiltered to recover the precipitate. The precipitate is thenrecrystallized to yield the desired product5-methylthio-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 18 Preparation of the Dimethyl Acetal of2-[1-Propyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde

A mixture of 5-methylthio-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05mole), the dimethyl acetal of 2-propylaminoacetaldehyde (0.1 mole) andbenzene (60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. The residue is then recrystallized to yield the desiredproduct the dimethyl acetal of2-[1-propyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde.

EXAMPLE 19 Preparation of 1-(5-Methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-propyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde(15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized to yield thedesired product 1-(5-methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 20 Preparation of 1-(5-Methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-hydroxy-1,3-imidazolidin-2-one (0.1 mole), morpholine (0.11mole) and benzene (100 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer, thermometer, reflux condenser andDean-Stark trap. The reaction mixture is heated at reflux, and the waterof reaction is removed as it is formed. After no more water is formed,the reaction mixture is stripped of solvent under reduced pressure toyield the desired product 1-(5-methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-morpholino-1,3-imidazolidin-2-one as the residue.

EXAMPLE 21 Preparation of 5-Methylsulfonyl-1,3,4-thiadiazol-2-ylIsocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-methylsulfonyl-2-amino-1,3,4-thiadiazole (50 grams) in ethylacetate (300 ml) is added to the reaction vessel, and the resultingmixture is stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture is then purged withnitrogen gas to remove unreacted phosgene. The purged mixture is thenfiltered to recover the precipitate. The precipitate is thenrecrystallized to yield the desired product5-methylsulfonyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 22 Preparation of the Dimethyl Acetal of2-[1-Allyl-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-methylsulfonyl-1,3,4-thiadiazol-2-yl isocyanate dimer(0.05 mole), the dimethyl acetal of 2-allylaminoacetaldehyde (0.1 mole)and benzene (60 ml) are charged into a glass reaction vessel equippedwith a mechanical stirrer and reflux condenser. The reaction mixture isheated at reflux for a period of about 15 minutes. After this time themixture is stripped of benzene under reduced pressure to yield a solidproduct as the residue. The residue is then recrystallized to yield thedesired product the dimethyl acetal of2-[1-allyl-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)-ureido]acetaldehyde.

EXAMPLE 23 Preparation of 1-(5-Methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-allyl-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml) arecharged into a glass reaction vessel equipped with a mechanical stirrer,thermometer and reflux condenser. The reaction mixture is heated atreflux for a period of about 15 minutes. The reaction mixture is thenfiltered while hot, and the filtrate is cooled to form a precipitate.The precipitate is recovered by filtration, is dried and isrecrystallized to yield the desired product1-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 24 Preparation of 1-(5-Methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one (0.1 mole), morpholine (0.11mole) and benzene (100 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer, thermometer, reflux condenser andDean-Stark trap. The reaction mixture is heated at reflux, and the waterof reaction is removed as it is formed. After no more water is formed,the reaction mixture is stripped of solvent under reduced pressure toyield the desired product 1-(5-methysulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-morpholino-1,3-imidazolidin-2-one.

EXAMPLE 25 Preparation of 5-Methylsulfinyl-1,3,4-thiadiazol-2-ylIsocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-methylsulfinyl-2-amino-1,3,4-thiadiazole (50 grams) in ethylacetate (300 ml) is added to the reaction vessel, and the resultingmixture is stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture is then purged withnitrogen gas to remove unreacted phosgene. The purged mixture is thenfiltered to recover the precipitate. The precipitate is thenrecrystallized to yield the desired product5-methylsulfinyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 26 Preparation of the Dimethyl Acetal of2-[1-Chloromethyl-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-methylsulfinyl-1,3,4-thiadiazol-2-yl isocyanate dimer(0.05 mole), the dimethyl acetal of 2-chloromethylaminoacetaldehyde (0.1mole) and benzene (60 ml) are charged into a glass reaction vesselequipped with a mechanical stirrer and reflux condenser. The reactionmixture is heated at reflux for a period of about 15 minutes. After thistime the mixture is stripped of benzene under reduced pressure to yielda solid product as the residue. The residue is then recrystallized toyield the desired product the dimethyl acetal of2-[1-chloromethyl-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde.

EXAMPLE 27 Preparation of1-(5-Methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-chloromethyl-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde(15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized to yield thedesired product1-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 28 Preparation of1-(5-Methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-hydroxy-1,3-imidazolidin-2-one(0.1 mole), morpholine (0.11 mole) and benzene (100 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometer,reflux condenser and Dean-Stark trap. The reaction mixture is heated atreflux, and the water of reaction is removed as it is formed. After nomore water is formed, the reaction mixture is stripped of solvent underreduced pressure to yield the desired product1-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-morpholino-1,3-imidazolidin-2-oneas the residue.

EXAMPLE 29 Preparation of 5-Cylopropyl-1,3,4-thiadiazol-2-yl IsocyanateDimer

A saturated solution of phosgene in ethyl acetate (100 ml) was chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-cyclopropyl-2-amino-1,3,4-thiadiazole (6 grams) in ethylacetate (100 ml) was added to the reaction vessel, and the resultingmixture was stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture was then purged withnitrogen gas to remove unreacted phosgene. The purged mixture wasfiltered to recover the desired product5-cyclopropyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 30 Preparation of the Dimethyl Acetal of2-[1-Propargyl-3-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-cyclopropyl-1,3,4-thiadiazol-2-yl isocyanate dimer (7grams), the dimethyl acetal of 2propargylaminoacetaldehyde (5 grams) andethyl acetate (50 ml) were charged into a glass reaction vessel equippedwith a mechanical stirrer and reflux condenser. The reaction mixture isheated at reflux for a period of about 2 hours. After this time themixture is stripped of solvent under reduced pressure to yield thedesired product the dimethyl acetal of2-[1-propargyl-3-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)ureido]-acetaldehydeas an oil.

EXAMPLE 31 Preparation of1-(5-Cyclopropyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-propargyl-3-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehydeobtained from Example 30, water (400 ml) and hydrochloric acid (4 ml)are charged into a glass reaction vessel equipped with a mechanicalstirrer, thermometer and reflux condenser. The reaction mixture isheated at reflux for a period of about 15 minutes. The reaction mixtureis then filtered while hot, and the filtrate is cooled to form aprecipitate. The precipitate is recovered by filtration, is dried and isrecrystallized from ethyl acetate to yield the desired product1-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 32 Preparation of1-(5-Cyclopropyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-morpholino--imidazolidin-2-one

1-(5-Cyclopropyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolidin-2-one(0.1 mole), morpholine (0.11 mole) and benzene (100 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometer,reflux condenser and Dean-Stark trap. The reaction mixture is heated atreflux, and the water of reaction is removed as it is formed. After nomore water is formed, the reaction mixture is stripped of solvent underreduced pressure to yield the desired product1-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-morpholino-1,3-imidazolidin-2-oneas the residue.

EXAMPLE 33 Preparation of 5-Cyclohexyl-1,3,4-thiadiazol-2-yl IsocyanateDimer

A saturated solution of phosgene in ethyl acetate (500 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer.5-Cyclohexyl-2-amino-1,3,4-thiadiazole (6 grams) is added to thereaction vessel, and the resulting mixture is stirred and heated atreflux for a period of about 4 hours, resulting in the formation of aprecipitate. The reaction mixture is then purged with nitrogen gas toremove unreacted phosgene. The purged mixture is then filtered torecover the precipitate. The precipitate is then recrystallized from adimethyl formamide-water mixture to yield the desired product5-cyclohexyl-1,3,4-thiadiazol-2-yl isocyanate dimer having a meltingpoint of 237° to 239° C.

EXAMPLE 34 Preparation of the Dimethyl Acetal of2-[1-Methyl-3-(5-cyclohexyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-cyclohexyl-1,3,4-thiadiazol-2-yl isocyanate dimer (12grams), the dimethyl acetal of 2-methylaminoacetaldehyde (6.9 grams) andbenzene (60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. The residue is then recrystallized from methanol toyield the desired product the dimethyl acetal of2-[1-methyl-3-(5-cyclohexyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehydehaving a melt point of 133° to 134° C.

EXAMPLE 35 Preparation of1-(5-Cyclohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-cyclohexyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde(15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized from methanolto yield the desired product1-(5-cyclohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-onehaving a melt point of 154° to 155° C.

EXAMPLE 36 Preparation of1-(5-Cyclohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one

1-(5-Cyclohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one(0.1 mole), morpholine (0.11 mole) and benzene (100 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometer,reflux condenser and Dean-Stark trap. The reaction mixture is heated atreflux, and the water of reaction is removed as it is formed. After nomore water is formed, the reaction mixture is stripped of solvent underreduced pressure to yield the desired product1-(5-cyclohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-oneas the residue.

EXAMPLE 37 Preparation of 5-Chloromethyl-1,3,4-thiadiazol-2-ylIsocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-chloromethyl-2-amino-1,3,4-thiadiazole (10 grams) in ethylacetate (300 ml) is added to the reaction vessel, and the resultingmixture is stirred for a period of about 16 hours, resulting in theformation of a precipitate. The reaction mixture is then purged withnitrogen gas to remove unreacted phosgene. The purged mixture is thenfiltered to recover the desired product5-chloromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer as a solid.

EXAMPLE 38 Preparation of the Dimethyl Acetal of2-[1-Methyl-3-(5-chloromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-chloromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer (9.5grams), the dimethyl acetal of 2-methylaminoacetaldehyde (5.8 grams) andbenzene (60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. This product is recrystallized to yield the desiredproduct the dimethyl acetal of2-[1-methyl-3-(5-chloromethyl-1,3,4-thiadiazol-2-yl)ureido]-acetaldehyde.

EXAMPLE 39 Preparation of1-(5-Chloromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy--imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-chloromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde(15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged intoa glass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled, resulting in the formation of aprecipitate. The precipitate is recovered by filtration, is dried and isrecrystallized from an ethyl acetate-hexane mixture to yield the desiredproduct1-(5-chloromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one.

EXAMPLE 40 Preparation of1-(5-Chloromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3-chloromorpholino)-1,3-imidazolidin-2-one

1-(5-chloromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one (0.1 mole), 3-chloromorpholine(0.11 mole) and benzene (100 ml) are charged into a glass reactionvessel equipped with a mechanical stirrer, thermometer, reflux condenserand Dean-Stark trap. The reaction mixture is heated at reflux, and thewater of reaction is removed as it is formed. After no more water isformed, the reaction mixture is stripped of solvent under reducedpressure to yield the desired product1-(5-chloromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3-chloromorpholino)-1,3-imidazolidin-2-oneas the residue.

EXAMPLE 41 Preparation of 5-Allyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer

A saturated solution of phosgene in ethyl acetate (100 ml) is chargedinto a glass reaction vessel equipped with a mechanical stirrer. Aslurry of 5-allyl-2-amino-1,3,4-thiadiazole (50 grams) in ethyl acetate(300 ml) is added to the reaction vessel, and the resulting mixture isstirred for a period of about 16 hours, resulting in the formation of aprecipitate. The reaction mixture is then purged with nitrogen gas toremove unreacted phosgene. The purged mixture is then filtered torecover the precipitate. The precipitate is then recrystallized to yieldthe desired product 5-allyl-1,3,4-thiadiazol-2-yl isocyanate dimer.

EXAMPLE 42 Preparation of the Dimethyl Acetal of2-[1-Methyl-3-(5-allyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde

A mixture of 5-allyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole),the dimethyl acetal of 2-methylaminoacetaldehyde (0.1 mole) and benzene(60 ml) are charged into a glass reaction vessel equipped with amechanical stirrer and reflux condenser. The reaction mixture is heatedat reflux for a period of about 15 minutes. After this time the mixtureis stripped of benzene under reduced pressure to yield a solid productas the residue. The residue is then recrystallized to yield the desiredproduct the dimethyl acetal of2-[1-methyl-3-(5-ally-1,3,4thiadiazol-2-yl)ureido]acetaldehyde.

EXAMPLE 43 Preparation of1-(5-Allyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one

The dimethyl acetal of2-[1-methyl-3-(5-allyl-1,3,4-thiadiazol-2-yl)ureido] acetaldehyde (15grams), water (400 ml) and hydrochloric acid (4 ml) are charged into aglass reaction vessel equipped with a mechanical stirrer, thermometerand reflux condenser. The reaction mixture is heated at reflux for aperiod of about 15 minutes. The reaction mixture is then filtered whilehot, and the filtrate is cooled to form a precipitate. The precipitateis recovered by filtration, is dried and is recrystallized to yield thedesired product1-(5-allyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxyl-1,3-imidazolidin-2-one.

EXAMPLE 44 Preparation of1-(5-Allyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3-methylmorpholino)-1,3-imidazolidin-2-one

1-(5-Allyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-hydroxy-1,3-imidazolidin-2-one(0.1 mole), 3-methylmorpholine (0.11 mole) and benzene (100 ml) arecharged into a glass reaction vessel equipped with a mechanical stirrer,thermometer, reflux condenser and Dean-Stark trap. The reaction mixtureis heated at reflux, and the water of reaction is removed as it isformed. After no more water is formed, the reaction mixture is strippedof solvent under reduced pressure to yield the desired product1-(5-allyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3-methylmorpholino)-1,3-imidazolidin-2-oneas the residue.

Additional compounds within the scope of the present invention which canbe prepared according to the procedures detailed in the foregoingexamples are1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-methyl-1,3,4-thiadiazol-2-yl)-3-butyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-ethyl-1,3,4-thiadiazol-2-yl)-3-pentyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-isopropyl-1,3,4-thiadiazol-2-yl)-3-hexyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-pentyl-1,3,4-thiadiazol-2-yl)-3-but-3-enyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-hexyl-1,3,4-thiadiazol-2-yl)-3-pent-4-enyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-cyclobutyl-1,3,4-thiadiazol-2-yl)-3-hex-4-enyl-5-morpholino-1,3-imidazolidin-2-one,1-5-cyclopentyl-1,3,4-thiadiazol-2-yl)-3-β-chloroethyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-cycloheptyl-1,3,4-thiadiazol-2-yl)-3-β-bromoethyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-but-3-enyl-1,3,4-thiadiazol-2-yl)-3-γ-chloropropyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-pent-4-enyl-1,3,4-thiadiazol-2-yl)-3-δ-chlorohexyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-hex-4-enyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-β-bromoethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-γ-chloropropyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-δchlorobutyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-β-bromohexyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-ethoxy-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-butoxy-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-hexyloxy-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-ethylthio-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-propylthio-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-hexylthio-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-ethylsulfonyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-butylsulfonyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-hexylsulfonyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,1-(5-ethylsulfinyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3,5-dibromomorpholino-1,3-imidazolidin-2-one,1-(5-propylsulfinyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3-hexylmorpholino)-1,3-imidazolidin-2-one,1-(5-hexylsulfinyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-(3,5-diethylmorpholino)-1,3-imidazolidin-2-oneand the like.

For practical use as herbicides the compounds of this invention aregenerally incorporated into herbicidal compositions which comprise aninert carrier and a herbicidally toxic amount of such a compound. Suchherbicidal compositions, which can also be called formulations, enablethe active compound to be applied conveniently to the site of the weedinfestation in any desired quantity. These compositions can be solidssuch as dusts, granules, or wettable table powders; or they can beliquids such as solutions, aerosols, or emulsifiable concentrates.

For example, dusts can be prepared by grinding and blending the activecompound with a solid inert carrier such as the talcs, clays, silicas,pyrophyllite, and the like. Granular formulations can be prepared byimpregnating the compound, usually dissolved in a suitable solvent, ontoand into granulated carriers such as the attapulgites or thevermiculites, usually of a particle size range of from about 0.3 to 1.5mm. Wettable powders, which can be dispersed in water or oil to anydesired concentration of the active compound, can be prepared byincorporating wetting agents into concentrated dust compositions.

In some cases the active compounds are sufficiently soluble in commonorganic solvents such as kerosene or xylene so that they can be useddirectly as solutions in these solvents. Frequently, solutions ofherbicides can be dispersed under super-atmospheric pressure asaerosols. However, preferred liquid herbicidal compositions areemulsifiable concentrates, which comprise an active compound accordingto this invention and as the inert carrier, a solvent and an enulsifier.Such emulsifiable concentrates can be extended with water and/or oil toany desired concentration of active compound for application as spraysto the site of the weed infestation. The emulsifiers most commonly usedin these concentrates are nonionic or mixtures of nonionic with anionicsurface-active agents. With the use of some emulsifier systems aninverted emulsion (water in oil) can be prepared for direct applicationto weed infestations.

A typical herbicidal composition according to this invention isillustrated by the following example, in which the quantities are inparts by weight.

    ______________________________________                                        Example 45                                                                            Preparation of a Dust                                                 ______________________________________                                                Product of Example 4                                                                        10                                                              Powdered Talc 90                                                      ______________________________________                                    

The above ingredients are mixed in a mechanical grinder-blender and areground until a homogeneous, freeflowing dust of the desired particlesize is obtained. This dust is suitable for direct application to thesite of the weed infestation.

The compounds of this invention can be applied as herbicides in anymanner recognized by the art. One method for the control of weedscomprises contacting the locus of said weeds with a herbicidalcomposition comprising an inert carrier and as an essential activeingredient, in a quantity which is herbicidally toxic to said weeds, acompound of the present invention. The concentration of the newcompounds of this invention in the herbicidal compositions will varygreatly with the type formulation and the purpose for which it isdesigned, but generally the herbicidal compositions will comprise fromabout 0.05 to about 95 percent by weight of the active compounds of thisinvention. In a preferred embodiment of this invention, the herbicidalcompositions will comprise from about 5 to about 75 percent by weight ofthe active compound. The compositions can also comprise such additionalsubstances as other pesticides, such as insecticides, nematocides,fungicides, and the like; stabilizers, spreaders, deactivators,adhesives, stickers, fertilizers, activators, synergists, and the like.

The compounds of the present invention are also useful when combinedwith other herbicides and/or defoliants, dessicants, growth inhibitors,and the like in the herbicidal compositions heretofore described. Theseother materials can cmprise from about 5% to about 95% of the activeingredients in the herbicidal compositions. Use of combinations of theseother herbicides and/or defoliants, dessicants, etc. with the compoundsof the present invention provide herbicidal compositions which are moreeffective in controlling weeds and often provide results unattainablewith separate compositions of the individual herbicides. The otherherbicides, defoliants, dessicants and plant growth inhibitors, withwhich the compounds of this invention can be used in the herbicidalcompositions to control weeds, can include chlorophenoxy herbicides suchas 2,4 -D, 2,4,5 -T, MCPA, MCPB, 4(2,4-DB), 2,4-DEB, 4-CPB, 4-CPA,4-CPP, 2,4,5-TB, 2,4,5-TES, 3,4-DA, silvex and the like; carbamateherbicides such as IPC, CIPC, swep, barban, BCPC, CEPC, CPPC, and thelike; thiocarbamate and dithiocarbamate herbicides such as CDEC, methamsodium, EPTC, diallate, PEBC, perbulate, vernolate and the like;substituted urea herbicides such as norea, siduron, dichloral urea,chloroxuron, cycluron, fenuron, monuron, monuron TCA, diuron, linuron,monolinuron, neburon, buturon, trimeturon and the like; symmetricaltriazine herbicides such as simazine, chlorazine, atraone, desmetryne,norazine, ipazine, prometryn, atrazine, trietazine, simetone, prometone,propazine, ametryne and the like; chloroacetamide herbicides such asalpha-chloro-N,N-dimethylacetamide, CDEA, CDAA,alpha-chloro-N-isopropylacetamide, 2-chloro-N-isopropylacetanilide,4-(chloroacetyl)morpholine, 1-(chloroacetyl)-piperidine and the like;chlorinated aliphatic acid herbicides such as TCA, dalapon,2,3-dichloropropionic acid, 2,2,3-TPA and the like; chlorinated benzoicacid and phenylacetic acid herbicides such as 2,3,6-TBA, 2,3,5,6-TBA,dicamba, tricamba, amiben, fenac, PBA,2-methoxy-3,6-dichlorophenylacetic acid,3-methoxy-2,6-dichlorophenylacetic acid,2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoicacid and the like; and such compounds as aminotriazole, maleichydrazide, phenyl mercuric acetate, endothal, biuret, technicalchlordane, dimethyl 2,3,5,6-tetrachloroterephthalate, diquat, erbon,DNC, CNBP, dichlorbenil, DPA, diphenamid, dipropalin, trifluralin,solan, dicryl, merphos, DMPA, DSMA, MSMA, potassium azide, acrolein,benefin, bensulide, AMS, bromacil,2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione,bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone,diphenatril, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, IPX, isocil, potassiumcyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP,picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA,brominil, CP-50144, H-176-1, H-732, M-2901, planavin, sodiumtetraborate, calcium cyanamid, DEF, ethyl xanthogen disulfide, sindone,sindone B, propanil and the like. Such herbicides can also be used inthe methods and compositions of this invention in the form of theirsalts, esters, amides, and other derivatives whenever applicable to theparticular parent compounds.

Weeds are undesirable plants growing where they are not wanted, havingno economic value, and interfering with the production of cultivatedcrops, with the growing of ornamental plants, or with the welfare oflivestock. Many types of weeds are known, including annuals such aspigweed, lambsquarters, foxtail, crabgrass, wild mustard, fieldpennycress, ryegrass, goose grass, chickweed, wild oats, velvetleaf,purslane, barnyardgrass, smartweed, knotweed, cocklebur, wild buckwheat,kochia, medic, corn cockle, ragweed, sowthistle, coffeeweed, croton,cuphea, dodder, fumitory, groundsel, hemp nettle, knawel, spurge,spurry, emex, jungle rice, pondweed, dog fennel, carpetweed,morningglory, bedstraw, ducksalad, naiad, cheatgrass, fall panicum,jimsonweed, witchgrass, switchgrass, watergrass, teaweed, wild turnipand sprangletop; biennials such as wild carrot, matricaria, wild barley,campion, chamomile, burdock, mullein, round-leaved mallow, bull thistle,hounds-tongue, moth mullein and purple star thistle; or perennials suchas white cockle, perennial ryegrass, quackgrass, Johnsongrass, Canadathistle, hedge bindweed, Bermuda grass, sheep sorrel, curly dock,nutgrass, field chickweed, dandelion, campanula, field bindweed, Russianknapweed, mesquite, toadflax, yarrow, aster, gromwell, horsetail,ironweed, sesbania, bulrush, cattail, winter-cress, horsenettle,nutsedge, milkweed and sicklepod.

Similarly, such weeds can be classified as broadleaf or grassy weeds. Itis economically desirable to control the growth of such weeds withoutdamaging beneficial plants or livestock.

The new compounds of this invention are particularly valuable for weedcontrol because they are toxic to many species and groups of weeds whilethey are relatively nontoxic to many beneficial plants. The exact amountof compound required will depend on a variety of factors, including thehardiness of the particular weed species, weather, type of soil, methodof application, the kind of beneficial plants in the same area and thelike. Thus, while the application of up to only about one or two ouncesof active compound per acre may be sufficient for good control of alight infestation of weeds growing under adverse conditions, theapplication of ten pounds or more of an active compound per acre may berequired for good control of a dense infestation of hardy perennialweeds growing under favorable conditions.

The herbicidal toxicity of the new compounds of this invention can beillustrated by many of the established testing techiques known to theart, such as pre- and post-emergence testing.

The herbicidal activity of the compounds of this invention wasdemonstrated by experiments carried out for the pre-emergence control ofa variety of weeds. In these experiments small plastic greenhouse potsfilled with dry soil were seeded with the various weed seeds.Twenty-four hours or less after seeding the pots were sprayed with wateruntil the soil was wet, and the product of Example 4,1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one,formulated as an aqueous emulsion of an acetone solution containingemulsifiers, was sprayed at the indicated concentrations on the surfaceof the soil.

After spraying, the soil containers were placed in the greenhouse andprovided with supplementary heat as required and daily or more frequentwatering. The plants were maintained under these conditions for a periodof from 15 to 21 days, at which time the condition of the plants and thedegree of injury to the plants was rated on a scale of from 0 to 10, asfollows: 0 = no injury, 1,2 = slight injury, 3,4 = moderate injury, 5,6= moderately severe injury, 7,8,9 = severe injury and 10 = death. Theeffectiveness of these compounds is demonstrated by data in Table I.

                                      TABLE I                                     __________________________________________________________________________                  Injury Rating                                                                 Injury Rating                                                   Weed Species                                                                            lbs/A:                                                                            8    4    2    1    1/2  1/4  1/8  1/16                         __________________________________________________________________________    Yellow Nutsedge                                                                             5    5    6    5    --   --   --   --                           Wild Oats     10   10   10   10   10   10   10   7                            Jimsonweed    6    7    6    4    9    10   7    3                            Velvetleaf    10   10   10   10   10   10   10   10                           Johnsongrass  9    10   9    10   9    9    7    3                            Pigweed       10   10   10   10   10   10   5    7                            Wild Mustard  10   10   10   10   10   10   10   10                           Yellow Foxtail                                                                              9    10   10   9    9    10   9    5                            Barnyardgrass 10   10   10   10   10   10   8    9                            Crabgrass     9    9    9    8    2    2    0    0                            Cheatgrass    10   10   10   10   10   10   6    4                            Morningglory  10   10   10   10   10   10   10   10                           Quackgrass    --   --   --   --   10   10   10   5                            Bindweed      --   --   --   --   10   9    3    3                            Sprangletop   --   --   --   --   10   6    3    3                            __________________________________________________________________________

The herbicidal activity of the compounds of this invention was alsodemonstrated by experiments carried out for the post-emergence controlof a variety of weeds. In these experiments1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-onewas formulated as an aqueous emulsion and sprayed at the indicateddosages on the foliage of the weeds that had attained a prescribed size.After spraying, the plants were placed in a greenhouse and watered dailyor more frequently. Water was not applied to the foliage of the treatedplants. The severity of the injury was determined 14 days aftertreatment and rated on the scale of from 0 to 10 heretofore described.The effectiveness of the compounds of this invention is demonstrated bythe data in Table II.

                                      TABLE II                                    __________________________________________________________________________                   Injury Rating                                                  Weed Species                                                                           lbs/acre:                                                                           1/2  1/4  1/8  1/16                                            __________________________________________________________________________    Crabgrass      6    4    4    0                                               Jimsonweed     10   8    10   10                                              Sprangletop    9    5    7    6                                               Yellow Foxtail 10   10   4    7                                               Pigweed        10   10   10   10                                              Cheatgrass     10   10   8    4                                               Barnyardgrass  9    9    5    0                                               Wild Oats      10   10   4    4                                               Velvetleaf     10   10   10   10                                              Bindweed       10   10   6    0                                               Wild Mustard   10   10   10   10                                              Johnsongrass   10   10   5    5                                               Morningglory   10   10   10   10                                              __________________________________________________________________________

I claim:
 1. A compound of the formula ##STR11## wherein R¹ is selectedfrom the group consisting of lower alkyl, cycloalkyl of from 3 to 7carbon atoms, lower alkenyl, lower chloroalkyl, lower bromoalkyl,trifluoromethyl, lower alkoxy, lower alkylthio, lower alkysulfonyl andlower alkylsulfinyl; R² is selected from the the group consisting oflower alkyl, lower alkenyl, lower haloalkyl and propargyl; X is selectedfrom the group consisting of lower alkyl and halogen; and n is aninteger from 0 to
 2. 2. The compound of claim 1,1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one.3. The compound of claim 1,1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-methyl-5-morpholino-1,3-imidazolidin-2-one.4. The compound of claim 1,1-(5-hexyl-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one.5. The compound of claim 1,1-(5-methoxy-1,3,4-thiadiazol-2-yl)-3-ethyl-5-morpholino-1,3-imidazolidin-2-one.6. The compounds of claim 1,1-(5-methylthio-1,3,4-thiadiazol-2-yl)-3-propyl-5-morpholino-1,3-imidazolidin-2-one.7. The compound of claim 1,1-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-morpholino-1,3-imidazolidin-2-one.8. The compound of claim 1,1-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-chloromethyl-5-morpholino-1,3-imidazolidin-2-one.9. A herbicidal composition comprising an inert carrier and, as anessential active ingredient, in a quantity toxic to weeds, a compound ofclaim
 1. 10. A method of controlling weeds which comprises contactingsaid weeds with a herbicidal composition comprising an inert carrierand, as an essential active ingredient, in a quantity toxic to weeds, acompound of claim 1.